1. Field of Invention
The present invention relates to an annular wrench.
2. Related Prior Art
Taiwanese Patent Publication No. 242807 discloses a toolbox/wrench with a case 10 for containing tool bits and a cover 16 for covering the case 10. The case 10 defines a hole 11 for receiving a toothed shaft 20 and a recess 12 for receiving a toothed pawl 23. The hole 11 is communicated with the recess 12, thus allowing engagement of the toothed shaft 20 with the toothed pawl 23. The toothed shaft 20 defines a hexagonal hole 21 for receiving a hexagonal shank of a connecting rod 34. The connecting rod 34 defines a hexagonal hole. In a first mode of operation, the hexagonal hole defined in the connecting rod 34 receives a hexagonal shank of a screwdriver 32. In a second mode of operation, the connecting rod 34 is engaged with a socket 31 via a second connecting rod 33. The second connecting rod 33 includes a hexagonal shank and a square shank. The socket 31 defines a square hole and a hexagonal hole. The hexagonal shank of the second connecting rod 33 is inserted in the hexagonal hole defined in the connecting rod 34. The square shank of the second connecting rod 33 is inserted in the square hole defined in the socket 31. The hexagonal hole defined in the socket 31 receives a nut or a head of a bolt. However, the case 10 cannot directly drive a tool bit such as a screwdriver or a socket. Furthermore, it is difficult to exert a large torque with the casing 10.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in the prior art.